Sheet-metal elbow



" (No Modem O. 8; A. LINDEMANN.

' SHEET METAL ELBOW.

No. 578,343. Patented Mar. 9, 1897.

UNITED STATES:

PAT NT OFFICE CHARLES LINDEMANN AND AUGUST LINDEMANN, OF MILWAUKEE,

WISCONSIN.

SHEET-M ETAL ELBOW.

SPECIFICATION forming part of Letters Patent N0. 578,343, dated March 9, 1897. Application filed August 23, 1890. Serial No. 362,814:- (No model.)

To aZZ whom it may concern:

Be it known that we, CHARLES LINDEMANN and AUGUST LINDEMANN, of Milwaukee, in the county of Milwaukee, and in the State of Wisconsin, have invented certain new and useful Improvements in Sheet-Metal Elbows; and we do hereby declare that the following is a full, clear, and exact description thereof.

Our invention has for its objects to provide for an economical use of material and to facilitate the manufacture of sheet-metal pipeelbows without detriment to the durability or appearance of the stock in the finished devices, these objects being attained as a result of certain peculiarities of construction hereinafter set forth with reference to the accompanying drawings and subsequently claimed.

. Figure 1 of the drawings represents a transverse section of a completed sheet-metalpipeelbow made in accordance with our invention, the plane of the section being indicated by line 1 1 in the succeeding figure. Fig. 2 represents a side elevation of the elbow.

Referring by letter to the drawings, A B represent the two sections that are embodied in a sheet-metal pipe-elbow made according to our invention, these sections being united by seams of any suitable form, the seams shown being such as are common in the art to which said invention pertains.

Instead of having the seams at the throat and back, as is common in the art of sheetmetal pipe-elbows, we locate them on lines intermediate of said throat and back, both longitudinal or seam edges of each section of the elbow being of like radius and length.

By division of the elbow,as above explained,

we provide for the utilization of blanks having a rectangular or approximately rectangw.

lar contour, and thereby we not only economize stock in cutting, but are also enabled to lessen the allowance ordinarily made for the rearrangement of metallic fibers incidental to the swaging operations by which the elbowsections are shaped from said blanks. Owing to the fact that in the manufacture of our elbows there is comparatively little rearrangement of the metallic fibers, the sections are easily swaged into shape without detriment to the appearance and durability of the stock in the finished devices, and it is to be understood that in shaping said sections from the blanks we employ separate dies for each and form the longitudinal seam-folds thereon coincident with the shaping.

The blank for the crown or back section A of the elbow is of less width than the one for the throat-section, and as said back-section takes up less of the circumference of said elbow than said throat-section the least allowance for draw or flow of metal incidental to the swaging operation is made in the former blank.

Owing to the fact that the blank for the throat-section B of the elbow has width considerably in excess of that for the back-section a great deal of draw would have to be taken up in the shaping of the former section by a swaging operation were it not for the fact that we overcome the difficulty by forming a plurality of crimps in the shortest curve of said throat-section. As a result of the crimps in the throat-section the amount of draw or flow of metal toward the longitudinal edges of this section is no greater than that of the back-section.

In the manufacture of our elbow, as above described, the rearrangement of the metallic fibers due to draw or flow of stock during the swaging operations necessary to shape the elbow-sections is reduced to a minimum, and

this rearrangement of said fibers is held within such limits that the longitudinal or seam edges of said elbow-sections, toward which the greatest amount of draw or How occurs, do not become hard or brittle, and thus we provide for strong seam-folds, while at the same time the finished surface or coating of the metal does not become wrinkled or marred in any way. We are also enabled to employ a lighter grade of stock than is usual in the art to which our invention relates.

It is to be understood that the rearrangement of the metallic fibers in the elbow-stock is gaged upon that necessarily occurring in the minor or back section, and the crimping of the major or throat section is made sufficient to compensate for all draw or flow of said stock that would bein excess of an amount corresponding to that in the former non-crimped section. Hence the actual draw or flow of stock in both sections is approximately equal, whereby the meeting or seam edges of these sections have the same density and ductility, the latter being but little less than that of said stock before the swaging of said elbow-sections is accomplished.

The finished elbow-sections may be nested for storage or shipment and put together by the dealer to form elbows, the form of the seam edges being such as to permit a ready and secure union of the sections necessary in each elbow. The sections of each elbow may be shaped to have the seams come upon the outside or inside of the finished article, as may be preferred, this being merely a matter of taste in the disposition of said seams.

Having now fully described our invention,

Wisconsin, in the presence of two witnesses. 0

CHARLES LINDEMANN. AUGUST LINDEMANN.

Witnesses:

N. E. OLIPHANT, WM. KLUG. 

